nanshe/__init__.py: Fix link to `rank_filter` so it points to the new organization.
nanshe/__init__.py: Fix link to `rank_filter` so it points to the new organization.

nanshe-org/nanshe,DudLab/nanshe,nanshe-org/nanshe,jakirkham/nanshe,DudLab/nanshe,jakirkham/nanshe